1. Field of Invention
This invention relates to automatic screwdriver apparatus, and more particularly to such apparatus having means for continually feeding screws into position for emplacement by a power screwdriver.
2. Prior Art
It is acknowledged that power screwdrivers capable of automatic, sequential emplacement of screws have existed for some time. The first line of such apparatus consisted of automatic screwdrivers used in connection with screw strips or sticks which consisted of a rigid line of screws integrally attached end to end. Examples of such apparatus are disclosed in U.S. Pat. Nos. 3,356,112; 3,421,557; 3,157,212 and 3,299,499. Because of the rigid structure of the screw strip, loss of linear alignment was not a problem and jamming occurred primarily because of failure of the respective screws to properly seat prior to emplacement. The lead screw of the screw strip was typically severed by wrenching it from its attached position to the following screw strip members.
Because of the limited applications of screw strips, subsequent power screwdrivers were developed for the purpose of channeling free screws into an alignment position for engagement by a bit means such as disclosed in U.S. Pat. No. 3,783,491. This reference suggests the use of a magazine for feeding unconnected screws into a drive shaft for subsequent engagement by a bit. A subsequent magazine-type fastener tool utilizing nails is disclosed in U.S. Pat. No. 3,543,987. Utilization of such a magazine arrangement, however, involves substantial expense and adds bulk to the overall structure of the power screwdriver.
What is needed, therefore, is an automatic loading, power screwdriver which does not require a magazine for arrangement and feeding of screws into an alignment chamber for engagement by a bit or similar driving means. It would be further beneficial to have such a power screwdriver which requires minimal manual manipulation during use and incurs little or no jamming difficulty.